I've put together a 2-cell pack using a pair of 18650 cells. Mine are pcb-protected so they are about 69mm long, and most sleds only fit unprotected cells that are 66mm. I tried to mod a smaller sled, but results have not been reliable.

I need to wire a pair in series, then 2 pair in parallel to get longer (7-hour) 7.4v output. Looking around, the Keystone 1048 is made for the longer cells, and I'm leaning toward building a 4-cell pack using them. Contacts should make for easy soldering, but I'll need to find a way to get the two sleds mated/enclosed.

Battery Space has holders for 18650 cells that would keep them solidly connected, but they have no contacts. Has anyone tried to construct a multiple-cell battery holder from spare parts? Any advice from folks with previous experience (good or bad) would be appreciated. Thanks.

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Naiant X-X > SP-SPSB-1 > M10

stevetoney

Just solder them up using either solder tabs (if you 18650 batteries came with tabs) or short well insulated conductor wire and then wrap the whole she-bang in electrical tape leaving your terminal leads coming out from under the tape. I'm not sure where to get it, but if you want to get fancy you could wrap the pack up with colored plastic shrink. That's essentially how lots of battery packs are put together.

stevetoney

I use the button-top cells in my flashlight, and would prefer not to solder tabs onto unprotected cells. I'm leaning toward using the Keystone holders.

I understand, but FWIW, I've done it alot and it's no big deal. Just double check your battery polarities as you're soldering up your pack and believe me, if you get it wrong you know immediately. The spark you get when the wrong poles touch is a pretty solid clue...lol. But even then the only way you'll get a spark is if you complete/short the poles together. It's really not that easy to do by accident when you're putting together a pack...no more difficult than shorting poles together if you're...say...carrying a few AAs in your your pocket along with some pocket change. I keep my wire cutters handy just in case I get an overheating event and need to nip a wire quick-like, but I've never had to do that since the couple of times I've caused a short, the spark caused me to self correct immediately.

I guess I'm just saying apply common electro-mechanical sense. If you don't have much of that type of sense, then yeah maybe best not try it. LOL.

I went ahead and bought the Keystone 1048 sleds which hold the cells nicely. I'll solder one set of tabs together to wire 1 pair in series, and wire the two pairs in parallel for the longer run-time I need.

I haven't had much luck tracking down a hard case to hold the sleds that isn't overly large. Size is less critical if you are going to build a pack to fit into a taping bag than finding an enclosure to mount onto a road bike. The smaller, the better.

A couple of Hammond 1590G cases could work, but I'd prefer a larger single one. Can't seem to find a case just the right size; either 80mm x 80mm x 20mm, or 80mm x 40mm x 40mm. The Poly Cases seem to have a lot of wasted corner space. Thinking of just putting it into a ziplock bag, then a small nylon frame pack.